The data network of mobile operator O2 left millions of customers without access to the internet on their phones.

According to the report, O2 has responded to the outage with an official statement on their website.

O2 has confirmed it will compensate users affected by the technical fault that took the mobile network's data services offline.

"During December 6, 2018, Ericsson has identified an issue in certain nodes in the core network resulting in network disturbances for a limited number of customers in multiple countries using two specific software versions of the SGSN-MME (Serving GPRS Support Node - Mobility Management Entity)", Ericsson said, adding that a "limited number of customers" were affected. Ericsson's chief executive Borje Ekholm issued an apology in the late afternoon.

Neeraj Murarka, CTO of Bluzelle, a specialist in centralised and decentralised technology offered a warning to global mobile carriers.

Internally, it's likely that O2 and other providers will be seeking reperations from Ericsson. Indeed, if it was just human error, it is understandable and a statistical reality.

She added: 'Ericsson sincerely apologises to customers for the inconvenience caused'.

Muraraka said this is another example where a more "decentralided" approach should be adopted.

The day-long O2 outage impacted all of the operator's 25 million customers, as well as an additional seven million customers using Sky Mobile, Tesco Mobile and giffgaff, all of which use the same mobile infrastructure.

Around the United Kingdom, public transport systems, and card payment terminals were also affected by data outage.

Customers had also reported being unable to send and receive text messages but O2 said this issue had also been resolved.

SoftBank said earlier the outages stemmed from problems at exchanges for its high-speed wireless LTE network - known as 4G.

"This is a result of nationwide O2 outage. We are working with our service provider to resolve this as soon as possible".

The two firms said: "We fully appreciate it's been a poor experience and we are really sorry".

"The cause of [the] network issue is in certain nodes in the core network resulting in network disturbances for a limited number of customers across the world, including in the United Kingdom", said Marielle Lindgren.